Lithium-based cells or batteries often comprise cathodes of transition metal oxides which are used as intercalation compounds. The intercalation reaction involves the interstitial introduction of a guest species, namely, lithium into the host lattice of the transition metal oxide, essentially without structural modification of the host lattice. Such intercalation reaction is essentially reversible because suitable transition states are achieved for both the forward and reverse of the intercalation reaction.
However, transition metal oxides when used as active cathode materials in rechargeable lithium batteries, show a declining capacity during cyclic operation of the battery. This may be attributable to volume changes of the host material which takes place when lithium is inserted and extracted. Because of the rigidity of the structural network into which lithium is inserted, such insertion can lead to large perturbations of the structure involving partial or complete breakage of certain bonds which can irreversibly destroy the oxide structure, resulting in poor electrical performance for the cathode. Such structural breakdown can occur whether the structure has two dimensional characteristics of a layered structure, or a more rigid three dimensional network oxide lattice.
Therefore, what is needed is a new cathode active material based on vanadium oxide in a form which maintains its capacity and has good charge/discharge cyclic characteristics over its useful operating life. What is also needed is a method to form such vanadium oxide based materials.